[fedora-virt] Windows clock synchronization

["Ján ONDREJ (SAL)"]

On Mon, Jul 08, 2013 at 01:37:01PM -0400, Cole Robinson wrote:
> On 07/04/2013 02:03 AM, "Ján ONDREJ (SAL)" wrote:
> > Hello,
> > 
> > On Wed, Jul 03, 2013 at 11:08:48AM -0400, Cole Robinson wrote:
> >> On 07/03/2013 01:54 AM, "Ján ONDREJ (SAL)" wrote:
> >>> Hello,
> >>>
> >>> On Tue, Jun 25, 2013 at 03:01:15PM -0400, Cole Robinson wrote:
> >>>> On 06/24/2013 02:18 PM, Ján ONDREJ (SAL) wrote:
> >>>>> Hello,
> >>>>>
> >>>>>   I have clock synchronization problems with Fedora 18/KVM host and windows
> >>>>> server guests.  Different 64bit windows servers, all has some time
> >>>>> synchronization problems.
> >>>>>
> >>>>>   Some of them will slow down time until time difference is 60 seconds and
> >>>>> then clock is synchronizes from internet. But 60 seconds is a long time.
> >>>>> Kerberos authentication sometimes files due to time skew.
> >>>>>
> >>>>>   Some machines will run OK day or two, but then clock stops. After some
> >>>>> hours clock is synchronized again and continues to work properly.
> >>>>> Curious, that during time is stopped, server works properly (except kerberos
> >>>>> authentications, which is very time sensitive.
> >>>>>
> >>>>>   For example, attaching 2 graphs from 2 windows servers. They show time
> >>>>> difference measured by check_mk nagios plugin. 10k means 10000 seconds.
> >>>>>
> >>>>>   How I should set clock/time/NTP on these guests?
> >>>>>
> >>>>>   I have absolutelly no problems with Linux guests, they work perfectly.
> >>>>>
> >>>>
> >>>> Maybe try altering the guest config with:
> >>>>
> >>>>       <clock offset='utc'>
> >>>>         <timer name='pit' tickpolicy='delay'/>
> >>>>         <timer name='rtc' tickpolicy='catchup'/>
> >>>>       </clock>
> >>>>
> >>>> https://bugs.launchpad.net/nova/+bug/1011848
> >>>> https://bugzilla.redhat.com/show_bug.cgi?id=828332
> >>>>
> >>>> virt-manager/virt-install should be doing this by default.
> >>>
> >>> These didn't helped me to fix my problem. Also trying combinations
> >>> of these without success:
> >>>
> >>>   <clock offset='variable' adjustment='2' basis='utc'>
> >>>     <timer name='rtc' tickpolicy='catchup'/>
> >>>     <timer name='pit' tickpolicy='delay'/>
> >>>     <timer name='hpet' present='yes'/>
> >>>   </clock>
> >>>   <qemu:commandline>
> >>>     <qemu:arg value='-rtc-td-hack'/>
> >>>   </qemu:commandline>
> >>>
> >>> Any ideas? Is this a bug?
> >>>
> >>
> >> Possibly, please file a Fedora qemu bug and list all the info you've given here.
> > 
> > Looks like there are 2 different clock problems and looks like I can
> > identify, when they appear.
> > 
> > I have 2 types of machines, 1st with virtio drivers and 2nd without virtio
> > drivers (default hardware configurations).
> > 
> > 1st type - virtio drivers installed, version virtio-win-0.1-59.iso (or 52)
> > - clock sometimes stops working completelly. I see more hours same time
> >   on machine.
> > - screenshot image-virtio.png attached
> > 
> > 2nd type - IDE disk and default network (e1000?)
> > - clock skew is 0-80 seconds. It's better like for 1st type.
> > - screenshot image-novirtio.png attached
> > 
> > Looks like there are some problems with virtio drivers, which stops
> > clock. Now I will try, if I can avoid problems with only one virtio driver
> > (net or disk).
> > 
> > Are ther commercial customers using these drivers?
> > Also have problems?
> 
> Best way to get some response for these questions is to file a separate bug
> against the virtio-win component in Fedora, where all the virtio-win guys are
> watching.

Thanks, done.

https://bugzilla.redhat.com/show_bug.cgi?id=982459

Btw, it's a network driver, which causes this. With disk driver I have no
problems.

Now I am switching my guests to e1000 driver to workaround this problem.

					SAL